title: Inducing phase changes in crystals of macromolecules: status and perspectives for controlled crystal dehydration.
abstract: The increase in the number of large multi-component complexes and membrane protein crystal structures determined over the last few years can be ascribed to a number of factors such as better protein expression and purification systems, the emergence of high-throughput crystallization techniques and the advent of 3rd generation synchrotron sources. However, many systems tend to produce crystals that can be extremely heterogeneous in their diffraction properties. This prevents, in many cases, the collection of diffraction data of sufficient quality to yield useful biological or phase information. Techniques that can increase the diffraction quality of macromolecular crystals can therefore be essential in the successful conclusion of these challenging projects. No technique is universal but encouraging results have been recently achieved by carrying out the controlled dehydration of crystals of biological macromolecules. A new device that delivers a stream of air with a precisely controlled relative humidity to the complicated sample environment found at modern synchrotron beamlines has been conceived at the EMBL Grenoble and developed by the EMBL and the ESRF as part of the SPINE2 complexes project, a European Commission funded protein structure initiative. The device, the HC1b, has been available for three years at the ESRF macromolecular crystallography beamlines and many systems have benefitted from on-line controlled dehydration. Here we describe a standard dehydration experiment, highlight some successful cases and discuss the different possible uses of the device.
authors.affiliation: European Molecular Biology Laboratory, 6 Rue Jules Horowitz, BP 181, 38042 Grenoble, Cedex 9, France.
authors.forename: Silvia
authors.initials: S
authors.lastname: Russi
authors.forename: Douglas H
authors.initials: DH
authors.lastname: Juers
authors.forename: Juan
authors.initials: J
authors.lastname: Sanchez-Weatherby
authors.forename: Erika
authors.initials: E
authors.lastname: Pellegrini
authors.forename: Estelle
authors.initials: E
authors.lastname: Mossou
authors.forename: V Trevor
authors.initials: VT
authors.lastname: Forsyth
authors.forename: Julien
authors.initials: J
authors.lastname: Huet
authors.forename: Alexandre
authors.initials: A
authors.lastname: Gobbo
authors.forename: Franck
authors.initials: F
authors.lastname: Felisaz
authors.forename: Raphael
authors.initials: R
authors.lastname: Moya
authors.forename: Sean M
authors.initials: SM
authors.lastname: McSweeney
authors.forename: Stephen
authors.initials: S
authors.lastname: Cusack
authors.forename: Florent
authors.initials: F
authors.lastname: Cipriani
authors.forename: Matthew W
authors.initials: MW
authors.lastname: Bowler
mesh_terms: D000682:Amyloid / Q000737:chemistry; D003080:Cold Temperature; D018360:Crystallography, X-Ray / Q000295:instrumentation* / Q000379:methods; D003890:Desiccation / Q000295:instrumentation* / Q000379:methods; D006801:Humans; D046912:Multiprotein Complexes / Q000737:chemistry*; D044367:Phase Transition; D010735:Phosphoglycerate Kinase / Q000737:chemistry; D045331:Photosystem I Protein Complex / Q000737:chemistry; D017356:Synchrotrons / Q000295:instrumentation
chemical_list: D000682:Amyloid; D046912:Multiprotein Complexes; D045331:Photosystem I Protein Complex; D010735:Phosphoglycerate Kinase